An Israeli soldier stands near the West Bank city of Hebron during a search for three missing teenagers from nearby settlements. / Nasser Shiyoukhi, AP

by Michael Winter, USA TODAY

by Michael Winter, USA TODAY

Israeli forces intensified their search Friday for three Jewish teenagers, one of them a U.S. citizen, who disappeared Thursday night while hitchhiking in the West Bank.

Defense officials said they believe the three students from Jewish settlements were kidnapped near Hebron by Palestinian militants who want to trade them for jailed comrades. The teens were not identified.

But an al-Qaeda offshoot of the Sunni extremists sweeping through Iraq claimed responsibility for abducting the teens as retaliation for the killings of three militants by Israeli forces in November, Haaretz reported. Israeli officials were trying to determine whether the claim was true.

Prime Minister Benjamin Netanyahu blamed Hamas, which recently joined the Palestinian government after U.S.-brokered peace talks failed, and he convened senior military officials late Friday for the second meeting of the day.

U.S. Secretary of State John Kerry spoke with Netanyahu and Palestinian Authority President Mahmoud Abbas, the State Department said.

"Secretary Kerry has ... spoken to President Abbas to urge him to do everything possible to assist in the effort to find them. President Abbas assured him that he is doing so," a spokesman said.

An extremist Salafist group known as Dawlat al-Islam distributed pamphlets claiming responsibility for the abductions. The organization is linked to ISIS.

The State Department has issued a travel warning for Israel, the West Bank and the Gaza Strip.

The three youths were last seen trying to get a ride home from a yeshiva in the Jewish settlement of Gush Etzion, north of Hebron. Two boys are 16 years old, and the third is 19, said Haaretz, citing security officials.

A police spokesman said one of the teens called police to say only that the three had been abducted, the Associated Press reported. Israeli soldiers found a burned-out car along a highway near the town of Dura, which they were searching house to house, Channel 10 reported. It's not yet known if it was connected to the boys' disappearance.

Netanyahu spoke with the boys' families, telling them "I know that you are going through such a difficult time. Be strong. Israel will make every effort to bring your sons home, and I promise to be in contact with you."